HAR Analyzer

HAR Analyzer

A HAR file is the JSON record Chrome, Edge, Firefox, and Safari write when you save a network session. This tool reads one and answers the three questions you actually have about it: which requests were slow, which ones moved the most bytes, and which ones failed.

Drop the .har file in. The summary shows the request count, wall-clock span, transferred and decoded size, bytes saved by compression, and the number of failures, plus a per-type breakdown. The table lists every request sorted by start time, with an inline waterfall drawn from the recorded phase timings; hover a bar to read the blocked, DNS, connect, TLS, send, wait and receive values. Sort by duration or size to put the offenders on top, and filter by text, resource type or status class.

Export the filtered set as CSV or Markdown for an issue, or download a redacted .har with authorization headers, cookies, sensitive query values and bodies stripped, so the original can be shared with someone else. Nothing you see on screen leaves the tab until you click download, and the file is parsed in this tab — never uploaded.

Two HAR quirks are handled for you: unavailable timings are recorded as -1 and shown as unknown rather than negative, and TLS time is drawn inside the connect segment instead of beside it, which is how the 1.2 spec stores it.